Optical communications systems now routinely employ electro-optic devices (e.g., integrated optic or multi-functional chips) that utilize electrodes to modulate optical signals propagating through an optical waveguide formed in an optically transmissive substrate and optically coupled between an input optical fiber and one or more output optical fibers. The substrate typically comprises an electro-optic crystal, such as lithium niobate (LiNbO3), on which optical waveguides may be formed by various means. Generally in such optical modulators, one or more waveguides are formed proximate to the upper surface of the substrate, and one or more surface electrodes are deposited on the surface proximate to the waveguides. When a voltage is applied to the surface electrodes, the phase of the light propagating through the waveguide is advanced or retarded. This effect may be employed to produce an optically modulated signal.
While known electro-optic devices function adequately in moderate environments, their performance may quickly degrade when operating under atypical or harsh conditions (e.g., in an environment characterized by extreme temperatures, humidities, pressures, etc., or an environment that experiences flux in such characteristics). When operating in vacuum-like conditions, for example, the electro-optic substrate in which the waveguide is formed experiences chemical changes over time as oxygen and hydrogen ions disassociate from the substrate's surface. This may result in significant performance degradation. For this reason, known electro-optic devices are not designed for or well-suited for applications that require operation under extreme conditions, especially space applications (e.g., use within a fiber optic gyroscope deployed on a spacecraft). Additionally, the performance of conventional electro-optic devices is known to degrade with exposure to radiation, including x-ray radiation.
It should thus be appreciated that it would be desirable to provide a method for adapting known electro-optic devices for operation under atypical or harsh conditions, including vacuum-like environments and radiation rich environments. Furthermore, it would be desirable to provide a method for stabilizing the surface of the optically transmissive substrate employed in an electro-optic device configured for operation in space. Other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.